Just a wrapper Class for FIFO, obviously Array.shift do the job standalone.

Queue (FIFO)

var FIFO = (function () {
	'use strict';

	// Load Dependencies
	var _ = require('lodash');

	// Set default configurations
	var defaultConfig = {
		type: 'number',
		random: false,
		priorityFrequency: 3,
	}

	// Constructor
	function FIFO(type, random, priorityFrequency) {

		this.items = [];
		this._config = _.merge({}, defaultConfig, {
			type: type,
			random: random,
			priorityFrequency: priorityFrequency,
		});
		this._priorityFrequencyCurrent = 0;
		if (random)
			this._nums = [];

	}

	Object.defineProperties(FIFO.prototype, {
		'next': {
			enumerable: false,
			configurable: false,
			get: next
		},
		'type': {
			enumerable: false,
			configurable: false,
			get: function () {
				return this._config.type;
			}
		},
		'length': {
			enumerable: false,
			configurable: false,
			get: function () {
				return this.items.length
			}
		}
	})

	FIFO.prototype.add = add;
	FIFO.prototype.get = get;
	FIFO.prototype.list = list;
	FIFO.prototype.remove = remove;

	return FIFO;

	///////////

	function add(item) {

		var _self = this;

		// Converts to	object
		if (_.isString(item))
			item = {value: item};

		// Merge with a random or next id
		_.merge(item, {
			id: (function () {
				var id,
				    last = _.last(_self.items) || {id:0};

				if (_self._config.type === 'number')
					id = !!_self._config.random ?  randomGenerator(_self._nums) : last.id + 1;
				else
					id = item[_self._config.type] || item.value

				return id;

			}())
		})

		return this.items.push(item);
	}

	function get(idx) {
		return !!idx ? this.remove(idx) : this.next;
	}

	function list() {
		return this.items;
	}

	function remove(idx) {
		return this.items.splice(idx, 1)[0];
	}

	function next() {
		if (++this._priorityFrequencyCurrent < this._config.priorityFrequency)
			return this.items.shift();

		this._priorityFrequencyCurrent = 0;
		var nextPriority = _.findWhere(this.items, {priority: true});
		return this.get(this.items.indexOf(nextPriority));
	}

	function randomGenerator(nums) {
		var rand = Math.floor((Math.random() * 999) + 1);
		if (~nums.indexOf(rand))
			return randomGenerator();
		nums.push(rand);
		return rand;
	}

})();